How do recording artists lose their music publishing ?

Question

Most recently George Clinton and the P-funk empire lost their publishing to Westbound Records owners.
The Rolling Stones and Beatles do not own most of their lucrative catalogs .

Answer 1

A lot of artists sell the rights for a one time payment instead of collecting the royalties over time.

Sometimes a new artist will give the publishing rights to their record label as part of their recording/promotion contract. Probably not a good idea if you believe you are ever going to make the big time.